Memory cards are known in the art and contain intelligence in the form of a memory circuit or other electronic program. Some form of card reader reads the information or memory stored on the card. Such cards are used in many applications in today's electronic society, including video cameras, digital still cameras, smartphones, music players, ATMs, cable television decoders, toys, games, PC adapters, multi-media cards and other electronic applications. Typically, a memory card includes a contact or terminal array for connection through a card connector to a card reader system and then to external equipment. The connector readily accommodates insertion and removal of the card to provide quick access to the information and program on the card. The card connector includes terminals for yieldingly engaging the contact array of the memory card. Ejecting devices often are provided for facilitating inserting and ejecting the memory card to and from the card connector.
A typical memory card connector includes an insulating housing structure usually having a lateral terminal-mounting section across the rear of the connector. The contacts or terminals of the connector are mounted on this lateral section. An overlying shell substantially covers the insulating housing and includes a cover plate defining a top of a cavity for receiving a memory card. The housing may have one or two legs projecting at right angles forwardly from one or both sides of the lateral section to define opposite sides of the cavity. The shell has a pair of side walls overlying the side legs of the housing. For example, see Japanese Unexamined Patent Publication (Kokai) No. 2001-291552. As stated above, an ejecting device may be provided for facilitating inserting and ejecting the memory card. The ejecting device may include a slider movably mounted on the housing and engageable with the memory card for movement therewith.
The insulating housing of such connectors typically is molded of dielectric plastic material into the desired shape. The terminals are stamped and formed of a sheet metal material having a high resiliency, such as phosphor bronze. The metal shell is stamped and formed of a conductive sheet metal, such as stainless steel. The connector often is mounted on the top surface of a printed circuit board, and solder tail portions of the terminals are connected, as by a reflow soldering process, to appropriate circuit traces on the board. Metal securing nails and/or portions of the metal shell also are secured, as by soldering, to appropriate mounting pads on the circuit board. The heat generated by these soldering processes often create problems in deforming the housing of the connector. This is particularly true with the ever-increasing miniaturization of such memory card connectors, whereby the housings are considerably downsized, including reducing the height of the housing.
Specifically, when the plastic housing is cooled after a reflow soldering process, the plastic material of the housing tends to shrink because of the cooling, along with heat dissipation. In fact, there is a possibility that the card-receiving cavity of the connector becomes contracted or narrowed and makes it impossible to insert the card thereinto. For example, FIGS. 13 and 14 herein shows an insulating housing, generally designated 16, which includes a side wall section 18 and a mounting post 20 for insertion into an appropriate mounting hole in a printed circuit board. A metal shell 22 has a top cover plate 22a and a side wall plate 22b which overlies the outside of the side wall section of the housing. The metal shell and the housing define a card-receiving cavity 24. It can be seen in FIG. 13 that side wall section 18 normally should abut against the inside of side wall plate 22b of the metal shell and defines one side of cavity 24. It can be seen in FIG. 14 that side wall section 18 has shrunk or moved inwardly in the direction of arrow “A”, away from side wall plate 22b of the metal shell and into cavity 24, as a result of cooling after a heated soldering process. As stated above, this movement of the side wall section could even prevent a card from being inserted into cavity 24.
In order to solve this problem, various approaches have been made such as is shown in Japanese Patent No. 3177774 and the like, wherein a press-fit piece 4C is provided on a metal shell 4 and is engaged in a groove 3c of an insulative housing by a press-fit under pressure (see FIG. 1). The displacement of the insulating housing thereby is restricted by press-fitting an engaging piece stamped and formed from the metal shell into an engaging groove in the insulating housing under pressure. Unfortunately, such approaches create further problems because the press-fit engagement between the engaging components create residual stresses in the plastic material of the housing. In fact, when the side wall sections of the housing are made thinner in order to reduce the size and weight of the connector, such press-fit engagements can cause torsion and deflection of the side wall sections of the housing if not the entire body of the housing. The present invention is directed to solving this myriad of problems.